1. Field of the Invention
The present invention relates to an air conditioner for performing a cooling and a heating operation, and more particularly to a method and apparatus for performing a dry operation wherein the air conditioner switches between heating and cooling while a cooling mode to remove humidity from the room for establishing a pleasant environment therein.
2. Description of the prior art
Generally, an air conditioner can be classified into two types, one for heating and the other for cooling the room. There is an air conditioner for dual purpose of heating and cooling, and even an air conditioner having an air cleaning capability.
As illustrated in FIG. 1 ,an indoor unit of a cooling and heating apparatus for the cooling and heating functions is shown and this apparatus of course includes an outdoor unit (not shown).
Reference numeral 1 in FIG. 1 is a body (hereinafter referred to as indoor unit) having a lower air inlet 3 and an upper discharge outlet 5.
The discharge outlet 5 is provided at a right side thereof with a remotely controlled signal receiver 7 and is also provided with horizontal blades 11 and vertical blades 13.
Meanwhile, a remotely controlled unit 9 (hereinafter referred to as remocon) is mounted with a plurality of functional keys and timer keys.
FIG. 2 is a side view of the indoor unit installed at a wall.
The indoor unit 1 is provided with a bar-shaped indoor heat exchanger 15 and an indoor fan 17 is provided to circulate air.
Furthermore, the indoor unit 1 is provided with a duct member 19. An evaporated water dish 21 is provided to collect condensate.
In the inverter type air conditioner thus described, a four way valve 31 is activated (i.e., "on") during a heating mode to allow coolant to flow via a circulating loop which is formed by compressor 30 - four way valve 31 - indoor heat exchanger 15 - capillary vessel 50 - outdoor heat exchanger 40 - four way valve 31 - compressor 30. (see the dotted line arrows in FIG. 3)
Meanwhile, during the cooling mode, the four way valve 31 is rendered off to thereby allow the coolant to flow via a circulating loop which is formed by compressor 30 - four way valve 31 - outdoor heat exchanger 40 - capillary vessel 50 - indoor heat exchanger 15 - four way valve 31 - compressor 30. (see the solid line arrows of FIG. 3)
The four way valve 31 serves to control a passage so that the coolant can be circulated in solid line when the four way valve 31 is off, and when the four way valve 31 is on, the coolant is circulated in the direction of the dotted line arrows.
In the cooling and heating dual purpose air conditioner thus described when a user manipulates the remocon to press an operation/stop key (hereinafter referred to as operation key) and input a desired mode (by way of example, cooling) and established temperature Ts and an established air amount, a remote control signal corresponding to the key input is coded by a predetermined protocol and the signal thus coded is modulated and is transmitted in an ultra-red signal.
When the ultra-red signal is transmitted from the remocon 9 a remocon signal receiver 7 at the indoor unit 1 receives the same and transforms same to an electrical signal. The signal is then decoded to start operating the indoor unit 1, whereby an indoor fan 17 is rotated in response to the established air amount to draw the room air to be infused into the indoor unit 1 via the inlet 3.
When temperature of the room air is sensed by a temperature sensor (not shown), the indoor unit 1 compares the established temperature(Ts) and the room temperature(Tr) and if the room temperature(Tr) is higher than the established temperature(Ts), an operational frequency of the compressor 30 is determined by the difference between the room temperature(Tr) and the established temperature(Ts) to thereby drive the compressor 30.
When the compressor 30 is driven, a cooling cycle is formed along the solid arrow line according to the inactivated four way valve 31. When gaseous coolant of high temperature and high pressure discharged from the compressor 30 at the outdoor unit is conducted into the outdoor heat exchanger 40, the outdoor heat exchanger 40 serves to heat-exchange the gaseous compressed coolant which is thus condensed into liquefied coolant of low temperature and low pressure and conducted to the capillary vessel 50.
The liquefied coolant conducted to the capillary vessel 50 is expanded and becomes an easily evaporable coolant which is conducted to the indoor heat exchanger 15 disposed in the indoor unit 1. The coolant evaporates to cool the room air.
The cool air flow direction is controlled by the horizontal and vertical blades 11 and 13 disposed at the discharge outlet 5, and the gaseous coolant cooled by the indoor heat exchanger 15 is conducted back into the compressor 30 and changed into coolant gas to repeat the cooling cycle mentioned above.
Meanwhile, during the heating operation, the established temperature Ts and the indoor temperature (Tr) are compared and if the established temperature(Ts) is higher than the indoor temperature (Tr), the operational frequency is determined according to the difference between the established temperature (Ts) and the room temperature (Tr) to thereby drive the compressor.
When the compressor is driven, there is established a cooling cycle defined by the solid line illustrated in FIG. 3 according to the activation of the four way valve 31. When the gaseous coolant of high temperature and high pressure discharged from the compressor 30 is conducted into the indoor heat exchanger 15, the indoor heat exchanger 15 serves to heat exchange the air and cool the coolant which becomes a room temperature and high pressure liquid. Warm air can be discharged to the room via the discharge outlet 5 to thereby perform the heating operation.
The liquefied coolant is evaporated through the capillary vessel 50 and reduced in temperature and pressure before being conducted into the outdoor heat exchanger 40. The coolant in the outdoor heat exchanger 40 is heat-exchanged by the air blown by the outdoor fan 41 to be cooled and infused into the compressor 30, wherein the coolant is transferred to gaseous coolant.
In the air conditioner performing the cooling and heating operations according to the coolant cycle, it executes the cooling and humidifying operations until an established temperature is reached, and when the established temperature is reached, as illustrated in FIG. 4, a dry operation is performed wherein the indoor fan 17, outdoor fan 41, four way valve 31 and the compressor 30 automatically perform a predetermined pattern of heating H, cooling C, and blowing-only B (i.e., blowing air without the compressor being on) in one cycle (53 minutes).
However, there is a problem in the conventional dehumidifying operation in that room temperature is over-heated or over-cooled according to the size of the load in the internal space as illustrated in FIG. 4, so that pleasantness degree expressed in Predicted Percentage of Dissatisfied (PPD) felt by the user becomes very high to thereby give the user unpleasantness.